It updated to 14291 a few days back, and hasn't been right since.
-The settings app is only partly functional.
-The time in the top corner randomly freezes.
-The keyboard space button sometimes stops working.
-Store won't download anything.
-Updates won't download
-Random losses of internet connectivity
-Turning OFF cellular data via the quick access button crashes the phone.
and so on.

Soft reset gets the phone "functional" again if it's crashed.
Hard reset(s) didn't fix anything, it might have made things worse.
WDRT sits saying reading device information for a very long time, then generates a thor2 error.
(WDRT connects fine to my L920)

That would have been my first choice, but as I stated, updates don't download.

Anyway, it's solved.
I discovered the answer accidentally while trying something else. I had to tell WDRT the device wasn't found then plug the phone in powered off. It detected the phone as it booted and allowed me to start downloading the package.
When the package was downloaded, I had to do the same thing again to install it.